Now that Republicans have abandoned the you-scratch-my-back, I'll-scratch-yours earmark process, Democrats who still hold a majority in the Senate have to decide whether they'll try to prop up a system that seems to be collapsing all around them.

With the incoming House GOP majority dead set against earmarks and President Barack Obama urging a crackdown, defenders of earmarks - mostly Democrats but with a few Republicans mixed in - are swimming against a powerful tide.

Earmarking allows lawmakers to steer federal spending to pet projects in their states and districts. Earmarks take many forms. They can be road projects, improvements to home district military bases, sewer projects, economic development projects and even those Predator drone aircraft that are used to kill terrorists in Afghanistan and Pakistan.

They can also include tax breaks for a handful of specific companies, like a tax cut proposed years ago for manufacturers of hunting arrows.

The reason Capitol Hill's favor factory has churned out so many pork-barrel projects so successfully for so long is pretty simple: Everybody did it, Democrats and Republicans, liberals and conservatives.

Not anymore.

Critics like Sen. John McCain, R-Ariz., and incoming House Speaker John Boehner, R-Ohio, have railed against earmarks for years, even as they proliferated when Republicans controlled Congress. Slowly, the tide has turned in their favor.

Boehner promises that next year's spending bills won't have earmarks. The opinion of House Democrats doesn't matter much since they'll be stripped of most of their power under a Boehner-led regime.

But it was Monday's surprise announcement by Senate GOP leader Mitch McConnell of Kentucky in support of a two-year moratorium on earmarks that fundamentally shifted the paradigm. Until then, McConnell had been a strong defender of the practice. Banning earmarks wouldn't save money and would shift too much power to Obama, McConnell said in the days after the midterm congressional elections.

Despite deep misgivings among many old-timers, Republican senators followed McConnell's lead and endorsed a nonbinding moratorium on earmarks Tuesday evening by a voice vote in a closed meeting.

Earmark critics want to go further and are demanding a vote by the entire Senate to ban them for three years.

The move by the Senate GOP leaves Senate Democrats as the only faction of Congress in a position to try to save the practice - and their position doesn't seem very strong, since it's difficult to see how Boehner and McConnell would allow any earmark-laden bills to pass.

Thus far, however, some Senate Democrats seem to be in denial.

"I have an obligation to the people of Nevada to do what is important to Nevada, not what is important to some bureaucrat down here (in Washington) with green eyeshades," Senate Majority Leader Harry Reid, D-Nev., said. "So I am not going, personally, going to back off of bringing stuff back to Nevada."

Once limited to the most senior and powerful lawmakers, earmarking pet projects and grants mushroomed after Republicans took over Congress in 1995.

Then, GOP leaders like House Speaker Newt Gingrich of Georgia and Majority Whip Tom DeLay of Texas saw earmarks as a way to help endangered Republicans keep their seats and to reward lawmakers loyal to GOP leaders. Boehner, by contrast, has never sought an earmark.

Estimates vary, but earmarks went from more than 1,300 projects worth nearly $8 billion in 1994 to a peak of nearly 14,000 projects worth more than $27 billion in 2005, according to Citizens Against Government Waste, a watchdog group that opposes the practice.

Democrats cut back the number and cost of earmarks somewhat and presided over changes that made the process more transparent by requiring the sponsors of the specially targeted programs and grants to disclose them. That's made it easier for outsiders to track a "pay-to-play" system in which lobbyists and corporate executives showered lawmakers with campaign funds in exchange for earmarks.

The new Senate moratorium is a nonbinding statement. It doesn't outright block a lawmaker from seeking an earmark, and some GOP senators have said they still will try to find a way to win them.

"If the Obama administration and their bureaucrats in the federal agencies take action against the best interests of South Carolina, I will take swift action to correct their wrongs," Sen. Lindsey Graham, R-S.C., said.

Graham has been feuding with home-state GOP colleague Jim DeMint - a leader of the movement to ban earmarks - over an effort to win federal money for a project to deepen the Port of Charleston so it can accept larger ships.

Other Senate Republicans, like Lisa Murkowski of Alaska and Jim Inhofe of Oklahoma, maintain they'll also try to find a way to earmark regardless.

An earmark ban "is nothing more than a shell game that moves the money and the decision-making responsibility from Congress to the bureaucracy," Murkowski said in a statement.